1. Field of the Invention
This invention relates to an improved reversing valve construction and to improved parts therefor as well as to methods of making such a reversing valve construction and improved parts therefor.
2. Prior Art Statement
It is well known that reversing valve constructions for heat pump systems and the like have been provided wherein each includes a housing means carrying a movable piston-like valve member that controls port means of a valve seat means of the housing means through the relative position of passage means of the valve member relative to the port means.
For example, see the following four U.S. Pat. Nos.:
(1) 3,032,312--Greenawalt
(2) 3,056,574--Greenawalt
(3) 3,357,453--Mingrone et al
(4) 3,985,154--Hargraves
Each reversing valve construction of the above items (1)-(4) appears to have a rigid and non-flexible valve member disposed in sliding contact with its cooperating valve seat surface, the first three above items each having the valve seat means thereof formed by a separate part disposed and secured in the housing means and being provided with a flat surface against which a flat surface of the movable valve member engages and slides in sealing relation therewith whereas the above patent to Hargraves has the valve seat means formed from a non-formed part of a cylindrical tubular housing member so as to be provided with an arcuate surface against which an arcuate surface of the valve member slides in sealing relation therewith.
Actual production devices that appear similar to the above four patents were examined and those similar to Mingrone et al and Hargraves were found to have rigid metallic surfaces of the valve members to be disposed in sliding relation with respective metallic surfaces of the valve seat means, the device similar to the U.S. Pat. to Greenawalt, No. 3,032,312 was found to have a non-flexible and rigid plastic annular part forming the sliding surface of the valve member and being captured at its inner and outer peripheries by metallic retainers of the valve member whereby the entire valve member is rigid, and the device similar to the U.S. Pat. to Greenawalt, No. 3,056,574 was found to have the entire valve member formed of plastic material and of such a thickness that the same is not flexible.
To prevent inward deformation of the sidewall of the valve member by outside pressure thereon, the U.S. Pat. to Greenwalt, No. 3,032,312 has a reinforcing pin disposed transversely in the cavity of the valve member adjacent the valve seat surface.
It is also known to form ports through the side wall of a tubular member by drawing a small opening in the side wall means from inside the tubular member to the outside thereof by the method of pulling a bullet-shaped member through such small opening from the inside to the outside thereof whereby a drawn port is formed with a surrounding collar extending outwardly from the external side wall of the tubular member. Such tubular members have been utilized in the heat exchange field, such as for forming solar energy panels and the like.
For example, see the Mar. 14, 1977, Business Week article entitled "This Drill Puts The T Into Tubing."